C. Santacruz

Effects of Different Crystalloid Solutions on Hemodynamics, Peripheral Perfusion, and the Microcirculation in Experimental Abdominal Sepsis.

Background:Crystalloid solutions are used to restore intravascular volume in septic patients, but each solution has limitations. The authors compared the effects of three crystalloid solutions on hemodynamics, organ function, microcirculation, and survival in a sepsis model. Methods:Peritonitis was induced by injection of autologous feces in 21 anesthetized, mechanically ventilated adult sheep. After baseline measurements, animals were randomized to lactated Ringer’s (LR), normal saline (NS), or PlasmaLyte as resuscitation fluid. The sublingual microcirculation was assessed using sidestream dark field videomicroscopy and muscle tissue oxygen saturation with near-infrared spectroscopy. Results:NS administration was associated with hyperchloremic acidosis. NS-treated animals had lower cardiac index and left ventricular stroke work index than LR-treated animals from 8 h and lower mean arterial pressure than LR-treated animals from 12 h. NS-treated animals had a lower proportion of perfused vessels than LR-treated animals after 12 h (median, 82 [71 to 83] vs. 85 [82 to 89], P = 0.04) and greater heterogeneity of proportion of perfused vessels than PlasmaLyte or LR groups at 18 h. Muscle tissue oxygen saturation was lower at 16 h in the NS group than in the other groups. The survival time of NS-treated animals was shorter than that of the LR group (17 [14 to 20] vs. 26 [23 to 29] h, P < 0.01) but similar to that of the PlasmaLyte group (20 [12 to 28] h, P = 0.74). Conclusions:In this abdominal sepsis model, resuscitation with NS was associated with hyperchloremic acidosis, greater hemodynamic instability, a more altered microcirculation, and more severe organ dysfunction than with balanced fluids. Survival time was shorter than in the LR group.

Modulation of Dietary Lipid Composition During Acute Respiratory Distress Syndrome Systematic Review and Meta-Analysis

BACKGROUND Pharmaconutrition including omega-3 and competitive analogs of omega-6 fatty acids has been used to modulate the inflammatory response during acute respiratory distress syndrome (ARDS). The clinical benefit of this approach when assessed in prospective randomized clinical trials has been inconsistent. We tried to assess the reasons for the conflicting results, including the possible influence of the composition of the control solution. METHODS We collected data from studies listed in PubMed, Ovid, the Cochrane Database of Systematic Reviews, Embase, the U.S. National Institute of Health database, and the ARDSnet database up to March 2013. We included all trials that evaluated effects of enteral pharmaconutrition vs a control solution on mortality, ventilator-free days, length of stay (LOS) in the intensive care unit (ICU), and ICU-free days. A sensitivity analysis was carried out to study the influence of the lipid content of the control solution. RESULTS We found 7 eligible studies (802 patients; 405 randomized to pharmaconutrition). The aggregated results showed no overall effect on mortality (risk ratio [RR] = 0.83 [0.55-1.25], P = .37), but there was a mortality benefit when only studies in which pharmaconutrition was compared to a lipid-rich control solution were considered (RR = 0.57 [0.41-0.78], P < .001). ICU LOS was shorter in patients randomized to pharmaconutrition (RR = 0.5 [0.85-0.16]). CONCLUSION Use of enteral pharmaconutrition in patients with ARDS was associated with decreased mortality only when the comparator solution contained a greater amount of lipid than is currently recommended. Hence, there is insufficient evidence to support the use of enteral pharmaconutrition in ARDS.

ISCHEMIC CONDITIONING PROTECTS THE MICROCIRCULATION, PRESERVES ORGAN FUNCTION, AND PROLONGS SURVIVAL IN SEPSIS.

ABSTRACT Ischemic conditioning induces a series of cellular modifications that may prevent injury from further hypoxic episodes, but there are few data in sepsis. In this randomized controlled study, we evaluated the effects of ischemic conditioning on the microcirculation, organ function, and survival time in an ovine model of septic shock. Sepsis was induced in 14 anesthetized, mechanically ventilated adult sheep by injecting autologous feces into the abdominal cavity. Animals were then randomized to ischemic pre- and post-conditioning or no conditioning (both n = 7). Remote ischemic conditioning was performed by inflating the balloon of a catheter in the aortic bifurcation for 2 min, followed by a 4-min deflation period. The procedure was performed four times before sepsis induction and 4-hourly afterward. Animals were followed until death or for a maximum of 30 h. Hemodynamic, oxygenation, and microcirculatory variables were monitored. The conditioned group had higher mixed venous oxygen saturation from 8 h after randomization, higher cardiac index, and oxygen delivery from 16 h, and higher mean arterial pressure and lower lactate levels from 20 h. They also had greater renal blood flow, urine output, and creatinine clearance. Microcirculatory variables were better preserved in the conditioned than in the control group from 6 h after randomization: the median proportion of perfused vessels was 91 (89–93)% versus 89 (86–90)% (P = 0.024) and there was less heterogeneity. Oliguria, hypotension, and death occurred later in the conditioned than in the control group. In this sepsis model, remote ischemic pre- and post-conditioning therefore decreased organ dysfunction, preserved the microcirculation, and prolonged survival.

Pharmaconutrition in the Critically Ill Patient

Critically ill patients might benefit from specialized nutrients provided in addition to macro- and micronutrients. Initially, the theoretical basis for specialized nutrition support relates to the altered immune response associated with the prolonged inflammatory status. For instance, immune-enhancing or immune-modulating nutrition formulas have been considered as logical and attractive options in critically ill patients [1]. Subsequently, changes in the composition of nutritional formulas were brought to compensate for specific deficiencies.

Elevated endocan levels are associated with development of renal failure in ARDS patients.

Objectives The aim of the study was to determine whether plasma endocan levels were correlated with renal function in patients with acute respiratory distress syndrome (ARDS) and could predict the need for renal replacement therapy (RRT), as an indicator of acute renal dysfunction, during the ICU stay. Methods This was a post hoc analysis of prospectively collected data from 96 consecutive patients with ARDS (Berlin definition) who were not receiving RRT at diagnosis. Plasma endocan concentrations were measured using a quantitative ELISA method (Lunginov, France). We analyzed the predictive value of creatinine and endocan levels at diagnosis on the subsequent need for RRT using the area under the receiver operating characteristic curve (ROC AUC). We dichotomized values of creatinine (using a renal SOFA cut-off of 1.2 mg/dL) and endocan (best sensitivity and specificity based on the ROC curve) to predict need for RRT. All analyses were performed using SPSS 22.0 and a p value < 0.05 was considered as significant. Al values are presented as median with p25-75.

0727. Normal saline versus ringer´s lactate in experimental sepsis

The development of hyperchloremic acidosis associated with normal saline (NS) administration may be deleterious in septic shock.

0092. Ischemic pre/post-conditioning protects the microcirculation in experimental sepsis

Ischemic preconditioning induces complex physiological adaptations to improve the tolerance of cells and tissues to future ischemic episodes. This phenomenon has been most studied in myocardial cells but also occurs in other tissues.

0888. Administration of tetrahydrobiopterin (BH4) protects renal microcirculation after ischemia and reperfusion

Abdominal aortic aneurysm surgery with supra-renal clamping is associated with potential development of renal insufficiency. Ischemia and reperfusion (I-R) produced during the procedure induces endothelial dysfunction with a decrease in tetrahydrobiopterin (BH4), a cofactor used in nitric oxide synthesis.